Boyfriends best friend ...

My boyfriend and I went to my boyfriends best friends house yesterday to build a shed from like 10 am to 930 pm and of course I was watching them but every time my boyfriend wasn’t near his best friend, his best friend would stare at me . And when I looked at him he would look away. After they were done with the shed we were all sitting and talking and he would only look at me when I was talking cause my boyfriend was right there. Normally he wouldn’t start a conversation with me unless my boyfriend was no where around. And then we had a fire and he was doing everything he could to make me laugh. Then messaged me today (normally he messages my BF) and said thanks for coming I had a really good time. What do y’all think?